The present invention is directed to the field of sporting goods. More particularly, the present invention is directed to a helmet, such as a football helmet, with enhanced protection performance characteristics. The present application claims priority of provisional patent application Ser. No. 60/545,676 filed Feb. 17, 2004.
Over the course of many years, protective helmets have evolved for use in sporting activities and other pursuits for which there is a risk of head injury, including football, hockey, baseball, softball, lacrosse, roller skating, skate boarding, cycling, motorcycling, automobile racing, snowmobiling, skiing, horseback riding, climbing, construction work, police activities, firefighting, and military activities. Using football as an example, early helmets were made of sewn leather. Helmets evolved to molded plastic outer shells with suspension webbing on their interior. Later, the suspension webbing was replaced with other head fitting structures such as foam fit pads of various types, air filled bladders, and padding molded to fit a particular user's head. Variations of these concepts are used for protective helmets to the present day. The functions of these helmets is to absorb as much of the energy transmitted to the helmet by impact with another object, whether the object is equipment worn or used by another person, a body part of another person, the ground, or a structural object, as well as to deflect, to the extent possible, impacts which occur at an oblique angle to the helmet. The purpose of these helmets is to diminish the risk of head and brain injury resulting from the activities with respect to which the helmets are used. The most common head injuries that helmets are designed to reduce are brain concussions.
Over the past two decades, epidemiological data on concussions have been gathered. Using football as an example once again, in about 1999, an article in the Journal of the American Medical Association estimated that approximately 250,000 concussions are suffered annually by those participating in football. Many high profile professional football players in the National Football League (“NFL”) had their careers shortened due to brain concussion injuries. Notable examples are Troy Aikman, Steve Young, and Merle Hodge. Concern has been raised about the prevalence of concussions incurred by those playing football, and this concern has been widely reported.
As a result, the NFL has launched a comprehensive study on the occurrence of concussions. Through the analysis of game films showing the impacts which occurred when concussions were suffered by NFL players, the mechanics of impacts resulting in concussions are being understood. The purpose is to continually apply the knowledge which is gained toward the further development of a helmet which reduces the occurrence of concussions. The hard exterior plastic shells of the helmets most commonly used by NFL players and the interior foam fit padding and air filled bladders most commonly used as head fitting structures for these helmets have the ability to absorb a certain amount of the impact energy when a helmet impacts an object. The impact energy that is not absorbed by the helmet is transferred to the skull of the user of the helmet, which can result in injury that can range from a mild concussion to severe brain injury. The most popular helmet currently being used in the NFL is the VSR4 manufactured by Riddell, Inc. Riddell, Inc. has also recently introduced a newer helmet for use by NFL players, as well as those playing football in college and high school, called the Riddell Revolution. Each of these helmets is constructed with hardened plastic exterior shell and commonly includes a form of foam fitting pads and/or air filled bladders as a head fitting structure mounted within each shell.
In the course of the study of head and brain injuries resulting from impacts with the head, researchers have developed various indices that attempt to identify and select the part of a measured acceleration pulse resulting from a head impact that would most likely contribute to injury. A mathematical relationship which resulted from this research is known as the Head Injury Criterion (“HIC”). HIC was incorporated into the Federal Motor Vehicle Safety Standards by the National Highway Traffic Administration. Standardized tests measuring the HIC of helmets are widely accepted in evaluating the ability of helmets to diminish the risk of impact head injury. It has been reported that HIC values of 1,000 and above resulting from the test for HIC represent conditions of moderate to severe brain injury, HIC values between 850 and 1,000 are likely to correspond to conditions of mild brain injury, and HIC levels below about 700 are considered not to be severe enough to cause mild brain injury. Thus, the lower the HIC measured by the standardized test the more effective a helmet is likely to be in reducing brain injury due to impact. The development of HIC is discussed in Lawrence M. Ilson, Ph.D. and Carley C. Ward, Ph.D., “Mechanisms and Pathophysiology of Mild Head Injury,” Seminars in Neurology, Volume 14, No. 1, March 1994, pp. 8-18.
The Biomechanical Engineering Laboratory of Wayne State University has been in the forefront of research regarding brain injury from impact, in the development of the HIC and the standardized test to measure it, and in testing helmets to determine their HIC levels. The NFL has recommended that helmets developed for potential use in the NFL be tested by the Biomechanical Engineering Laboratory of Wayne State University.
In an attempt to further improve existing helmets, the inventor of this invention developed a helmet cover which could be placed over and secured to an existing helmet without modifying the helmet. This helmet cover was an elastomeric cellular, foam material having an integral inner skin and an integral outer skin. The foam material had physical characteristics which caused it to absorb energy from impact with another object, and rapidly and fully recover to absorb energy from the next impact, thereby reducing the potential for injury to the wearer of the helmet on which the helmet cover was mounted. This helmet cover is the subject of U.S. Pat. No. 4,937,888 issued to Albert E. Straus on Jul. 3, 1990. Knowledge gained from the development and use of the helmet cover on existing helmets and gained from a study of the continuing research discussed above had led to the development of a fully integrated helmet system which outperforms alternatives when measured by the latest laboratory standards, as well as the development of helmet subsystems which can be useful in other helmets.